Peppered Moth Survey

Industrial melanism is the term used to describe the adaptation of an organism in response to industrial pollution, One example of rapid industrial melanism occurred in the peppered moth, Biston betularia, in the area of Manchester, England from 1845 – 1890.

Before the Industrial Revolution, the trees in the forest around Manchester were light grayish-green due to the presence of lichens in their trunks. Peppered moths, which lived in the area, were light with dark spots. Their coloring served as camouflage against predators. As the Industrial Revolution progressed, the trees became covered with sulfur dioxide, turning the trunks dark. Over a period of 45 years, the peppered moths changed to a predominantly dark species, with only a few light-colored individuals remaining.

In this investigation, you will observe the effects of industrial melanism in the peppered moth over the course of several years.

The table below represents data from a ten-year study of two varieties of the same species of peppered moth. The numbers represent moths captured in traps for ten consecutive years. The traps were located in the same area each year.

Year / Number of light colored moths captured / Number of dark colored moths captured
1 / 556 / 64
2 / 537 / 112
3 / 484 / 198
4 / 392 / 210
5 / 246 / 281
6 / 225 / 357
7 / 193 / 412
8 / 147 / 503
9 / 84 / 594
10 / 56 / 638
Total / 2,920 / 3,369

Using the data provided, construct a graph comparing the numbers of each variety of peppered moth. Create a line graph that will have two variables (lines). One line will represent the light colored moths and the other line will represent the dark colored moths. Label the X axis years and the Y axis number of moths captured. Please try to place two graphs onto one page in word, print, cut, and then paste one in your lab notebook and one in your partner’s lab notebook.

Use your textbook, notes, and your graph to answer the following questions.

1.  What might use vision to prey on the peppered moth?

2.  If the bark of trees is dark and the moths that rest there are light what will happen to the moths?

3.  What is a mutation? Are all mutations bad, good, or equal?

4.  What could have caused the first moth to change from a light variety to a dark variety, providing some variation in the species?

5.  What event caused the tree trunks of many trees in England to turn from light to dark?

6.  Which variety of moth increased over the ten-year period?

7.  What is the name of the theory that could explain this evolutionary change?

8.  Using the data on the graph, draw a conclusion concerning the population of peppered moths in the sampled area of England if the trees were to remain dark in color.

9.  Explain the reason for the increase in the number of dark colored moths.

10.  What means could be used to return the environment of the peppered moth to its original state?

11.  What effect would cleaning up the environment have on the population of each type of moth?